Automatic valve controlling mechanism for electric circuit breakers



O 1951 J w. TIMMERMAN, JR 2,575,934

AUTOMATIC VALVE CONTROLLING MECHANISM FOR ELECTRIC CIRCUIT BREAKERSFiled Nov. 18, 1947 Fi l.

Inventor" Julius W. Timmerman Jn,

H is Attorney.

Patented Nov. 20, 1951 AUTOMATIC VALVE CONTROLLING MECHA- NISM FORELECTRIC CIRCUIT BREAKERS Julius W. Timmerman, Jr., Waukesha, Wis.,assignor to General Electric Company, a corporation of New YorkApplication November 18, 1947, Serial No. 786,594

8 Claims. 1

My invention relates to fluid control means for electric circuitbreakers and, more particularly, to an automatically operable mechanismfor controlling the degree of opening of a blast valve used to supplyfluid to a'circult breaker of the fluid actuated type.

Circuit breakers utilizing a blast of fluid to extinguish the are drawnbetween retractable contactsmay also utilize the fluid blast to performthe retracting action of the contacts and, therefore, the amount offluid required may be quite large. This is particularly true if thecircuit breaker is of the reclosing type where several operations may beperformed within a relatively short period of time, thus necessitatingthe use of a relatively large storage tank or reservoir for the fluid.

In circuit breakers employing biased-closed interrupting contacts, anisolating switch is placed in the main circuit in series with thecircuit breaker interrupting contacts. In such cases, after a circuitinterrupting operation is performed by the circuit breaker, the circuitbreaker interrupting contacts must be maintained in the open positionsufliciently long to permit the isolating switch to form a sufllcientisolating gap. The rate of flow and pressure of the fluid necessary tomaintain the circuit breaker interrupting contacts in the open positionafter interruption has been accomplished may be considerably less thanthat required for the dual purpose of both holding these contacts openand blasting the are drawn therebetween to extinction.

A principal object of my invention, therefore, is the provision'of meanswhereby the overall consumption of fluid may be substantially reducedthereby making possible a smaller fluid storage capacity than ordinarilywould be required for a particular circuit breaker application.

Another object of my invention is the provision of means for supplying arelatively large quantity of fluid for the purpose of causing thecircuit breaker contacts to separate and at the same time to blast thearc to extinction followed by a substantial reduction in the quantityand pressure of fluid supplied for the purpose of maintaining thecontacts separated and insulated from each other until such time as theisolating switch blade will have formed a suitable series isolating gap.

Still another object of my invention is the provision of means forinitially causing the main blast valve to assume its fully openedposition for a predetermined time and thereafter to revert to anintermediate or partially opened po- 2 siticn whereby the amount andpressure of fluid supplied to the circuit breaker may be reduced afterthe interruption of the circuit.

A further object of my invention is the provision of piston meansautomatically operableinresponse to pressure supplied from the fluidtank or reservoir for controlling the main blast valve and thereby toconserve the amount of fluid required to perform a circuit interruptingoperation.

Other objects and advantages of my invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawing, in which: Fig. 1 represents a circuit interrupting arrangementincorporating a blast valve operable by two piston members to opened,

conduit 14, branch conduits i6 and H to the circuit breakerschematically represented and generally indicated by the numeral l8.Fluid from auxiliary conduits l6 and I1 enters the circuit breakerhousing 20 to occupy chambers 22 and 24. Thus fluid pressure in thechambers 22 and 24 bears against the surfaces of pistons 28 and 2! towhich main contacts 32 and 30 are secured. The pressure of the fluidforces pistons 26 and 28 apart against the action of biasing springs 34and 36 to draw an are between contacts and 32 in the enclosure 38. Asthe contacts 30 and 32 pass through the throats 40 and 42 respectively,a blast of pressure fluid is caused to new from the chambers 22 and 24into the enclosure 38 where a blasting action takes place which issuiflcient to extinguish the arc and to expel the products of theinterrupting operation such as gas and other materials to atmospherethrough the exhaust vent 45.

The circuit interrupting operation may be initiated by manually closingthe switch schematically indicated at H which operation supplies acurrent from a source of potential, not shown. to the coil 46 which inturn picks up the armature 48 against the bias of spring 5,0 to causethe plug member 52 of pilot valve 53 to rotate counterclockwise due tothe upward movement of the arm 54 thereby causing the passage 56 in plugmango ically represented at 80 to energize the winding '00 of relay 02causing armature in to move upwardly thereby completing the circuit tothe re- .lay coil 40.

The valve mechanism oi Fig. 1 will now be described. RodJ2 is rigidlysecured as by a pin I4 to blast valve disc I2. Piston It is slidablewithin cylinder I0 and is secured to rod I2 by any suitable means suchas by pin I. Spring 82 may be used for the purpose of biasing piston It.rod I2 and'valve disk I2 to the closed position. A port such as 80 maybe provided in cylinder I8 to insure communication between atmosphere-and the underside of piston I6. Port 86 will prevent the entrapment offluid under piston It as for instance when the piston is movingdownwardly. If it is desired to utilize the cushioning effect of fluidunder piston It, the port it may be omitted. Piston 28 is slidablymounted on shaft I2 within cylinder 00. Spring 92 biases piston 00 awayfrom the common end wall or partition 04' which separates the twocylinders I8 and 40. Suitable ports or vents 93 may be drilled throughthe piston 00 in the direction of its axis. The capping member St issecured to the rod 12 in any suitable manner such as by a set screw 08.Radially extending ports I02 and I04 are provided in the hollow portionII of the rod I2. Needle valve I06 is slidably adjustable within thehollow portion III of the rod I2 for the purpose of controlling the flowof fluid from the hollow portion ml of the shaft I2 through the ventsI02 into the cylinder- 90. Thus, it will be seen that the ports I02 andI04, the hollow portion IOI of rod- 12 together with the central openingin partition 94 form an auxiliary valve interposed between cylinders I8and 90. The adjusting mechanism for needle valve I 08 may compriseinternal threads on the inner surface of hollow .portion III of rod I2at .the upper end of rod I2 and exend of rod I2 and which would engagethe external threads on needle valve I 06.

-As shown in Fig. l the valve I2 is inthe closed position. In thisposition there is no pressure in the portion 59 of conduit 58. Piston I6is biased upwardly by thespring 82 and a small clearance exists betweenthe upper surface of piston It and the lower surface of the common endwall 86. In the position shown in Fig. l the ports 83 are uncovered sothat atmospheric pressure may exist inside the cylinder 90. When thevalve I2 is in its intermediate and opened positionsthe capping member06 abuts against the upper surface of piston 08 to seal the ports 93.The clearance distance between the upper surface of piston 88 and thelower surface of capping member 96 is also the distance of travel ofvalve I2 and its assoelated parts from the intermediate position to theclosed position of valve l2 as will be more fully valve closed positionshown in Fig. i, the piston 00 is biased upwardly by its spring '2 intoabut ting relationship with the apertured outer. end wall 0I of cylinder00.

For the purpose of supplying a relatively large blast of pressure fluidto the circuit breaker II to perform a retracting operation of thecontacts 20 and 32 and also to blast the are drawn therebetween, it isnecessary to cause the valve I2 to assume its fully opened position. Toaccomplish full opening of the valve I2, plug member 52 o'f the pilotvalve 03 is rotated counterclockwise by energizing coil 4| eithermanually or through a current transformer as explained above. Pressurefluid from reservoir II passes through conduit ll, pilot valve 52,portion 59 of conduit 50 and .through an opening in the common end wallor partition '04 to the inside of cylinderflt. It will be observed thatports I04 in rod I2 are covered. Fluid pressure against the uppersurface of piston It will force that piston, the rod l2, and the valveI2 to move downwardly against the bias oi spring l2 until the valve I2has reached its fully fopened position. As the rod I2 moves downwardly,the capping member 86 engages the upper surface of piston "and forcesthat piston downwardly against the bias of spring 02. After the rod I2has moved a slight distance toward the fully opened position of valveI2, the ports I04 in rod I2 are uncovered as they clear the common endwall 84. Pressure fluid then passes from cylinder ll through ports I04,the hollow portion III of rod I2 and the ports I02 in rod I2 and thenceinto the cylinder 90. The rate at which pressure builds up in cylinder90 is controlled by the particular setting to which needle valve I06 hasbeen adjusted. Preferably the setting of needle valve I08. the size andposition of openings 502 and I04 will be chosen to permit valve I2 toreach its fully opened position and to remain in that position longenough to insure the extinguishment of the arm drawn between contacts 20and 32 of circuit breaker I8. It will be observed that the maxi- .mumtravel of piston I0 and rod I2 toward the opened position of valve I2 islimited by the shoulder I9 in the cylinder I0. Preferably the quantityof fluid allowed to pass into cylinder during the opening operation ofvalve I2 will be 'sufllcient to aii'ord a pneumatic cushioning actionwhich will .serve yieldably to arrest downward motion of piston 80 and,in turn, the downward motion oi valve i2, rod I2 and piston It. Asdiscussed above, the needle valve I06 will haveioeen so adiusted thatvalve I2 will be forced to remain open for a long enough time to permitestinguishment o! the arc between retractable contacts as and 32.

As explained above, in order toconserve the amount of fluid required toperform an interrupting operation, it is desirable. to reduce the fluidflow after the arc has been extinguished and pending the formation of asuillcient isolating gap by the series connected isolating switch. Toaccomplish this purpose in accordance with my invention. the valve iscausedto move toward its closed position to occupy an intermediate orpartially opened position which will reduce the quantity of fluid flowto an amount Just suiiicient to maintain the circuit breaker contacts intheir isolating po 0 Assuming that the main valve I2 is fully opened.the operation of my invention whereby the valve I2 is moved to itsintermediate position will now be explained. when the valve I2 isunderstood as the description proceeds. In the .7 fully opened.fluid-pressure .irom. portion SI. 0!

asraeee conduit 58 passes through openings I04. hollow portion I! of rod12, openings I02 and into the inside of cylinder 90. Because piston 08is of larger diameter than piston 16, the force exerted by piston 88 tocause rod 12 and valve I2 to'rnove toward the closed position will begreater than the force on the upper surface of piston I8 tend- 7 ing tohold valve It in the open position. This net force together with theaction of springs 92 and 82 will cause the valve to move towards theclosed position. Such movement will be arrested when piston 88 engagesthe shoulder 0| of cylinder 00. The pressure from portion 59 ofauxiliary conduit 58, hearing against the upper surface of piston I8,will be suflicient to maintain valve I! in its partially opened orintermediate position at a clearance distance equal to the normalclearance between the upper surface of piston 88 and the lower surfaceof capping member 86. The valve I2 will remain in this position so longas normal fluid pressure exists on the upper side of piston I8,

The pressure fluid allowed to pass through conduit I4 to circuit breakerI8, after the arc has been interrupted need be maintained only so longas may be necessary for the series connected isolatingswitch to assume asafe isolating position. When the isolating switch has assumed such aposition, it is desirable to permit the circuit breaker I8 to close inagain under the action of biasing springs 84 and 38 in order thatneedless waste of pressure fluid from reservoir I0 may be avoided. Tothis end valve I2 is, of course, allowedto assume its fully closedposition. To cause valve I2 to move from its intermediate position toits closed position it is only necessary, in accordance with myinvention, to close the pilot valve 53; and thereby to shut off thesupply of fluid from reservoir I0. When plug member 52 of valve 53 ismoved clockwise under the action of biasing spring 50, fluid pressurewithin the cylinder l8 and above piston I8, is allowed to escape toatmosphere through portion 59 of conduit 58, and exhaust vent 55 ofpilot valve 53. Biasing spring 82 will then force piston is and rod I2upwardly so as to cause capping member 98 to become disengaged frompiston 88 by a suitable normal clearance distance such as is indicatedin the drawing. This upward motion of rod 12 will be suiilcient to causevalve I2 to reach its fully closed position therehv shutting off furthersupply of fluid from reservoir I0 through conduit It to circuit breakerI8.

It will be observed that when the main valve I2 is closed, any fluidpressure which may exist withinfthe cylinder 90, and below the piston88, will be.-allowed to escape to atmosphere through the ports 93 inpiston 08 because of the clearance distance between piston 88 andcapping member 86. It; will also be observed that atmospheric pressureonly may exist within cylinder 18 and belowpiston I6 because of thecommunication throughport88 to atmosphere. The mechanism 80 is,therefore, automatically readied for a new cycle} of performance.

Fig. 2 represents a modification of my invention wherein like parts arerepresented by the same numerals as those used in connection with thedevice of Fig. 1. The device of Fig. 2 performs in a manner similar tothe performance of the device of Fig. 1 in that the device of Fig. 2provides for an initial inrush of pressure fluid to the breaker followedby a reduction in the quantity and pressure of fluid for the purpose ofconserving fluid from tank I0.

In the device of Fig. 2 the numeral I08 designates a piston slidablymounted in a cylinder I I0. The numeral II2 represents a biasing springfor the iston I08, rod I2 and valve I2 which spring serves to bias valveI2 to the closed position. The number H4 represents a conduit forsupplying fluid pressure to the underside of piston I08 while thenumeral I I8 represents a small fluid reservoir. A port H8 is providedin the wall of cylinder H0 and is located at a point intermediate thelimits of travel of piston I08 for the purpose of determining theintermediate position of valve I2 as will be better understood as thedescription proceeds.

In order for the device of Fig. 2 to cause the valve I2 to assume itsfully opened position, the valve 58 is opened in any suitable mannersuch as described in connection with the device in Fig. l. Fluidpressure then flows from reservoir I0, conduit 58, portion 58 of,conduit 88, and into the cylinder IIO above piston I08. This fluidpressure within cylinder IIO will operate to force piston I08, rod 12and valve I2 downwardly to the fully opened position of valve I2 and themaximum flow of fluid will be allowed to enter circuit breaker I8through conduit I4. The shoulder II8 within cylinder IIO serves as alimiting stop and determines the lower-most position of piston I08.After pilot valve 53 is opened, fluid pressure enters conduit I I4 whichmay be of smaller cross sectional area than conduit 58. Because of thesmaller cross sectional area of conduit Ill, the rate of flow of fluidtherethrough will be less than the rate of flow of fluid through portion59 of conduit 58 and hence the build-up of pressure within cylinder H0,below piston I08, will be less rapid than the build-up of pressure abovepiston I08. In this way initial downward movement of piston I08, andopening of valve I2, is accomplished. The relative sizes of conduit Illand portion 58 of conduit 58 as well as the size of spring II2 arepreferably chosen to permit valve I2 to remain in its fully openedposition until after the are drawn between retractable contacts 30 and32 has been extinguished. After extinguishment of the are drawn betweencontacts 30 and 32, sufficient pressure builds up within cylinder IIObelow piston I08 which together with the force of spring H2 will causepiston I08, rod I2 and valve I2 to move upwardly until piston I08uncovers bleed port H8, at which time some of the pressure below pistonI08 will be allowed to escape to atmosphere and a condition ofequilibrium for piston I08 will result when pressure above that pistonbalances the total valve closing force comprising the fluid pressurebelow the piston and the force exerted by the spring II2. This conditionof equilibrium will correspond to an intermediate position for valve I2and will, therefore, result in a. substantial reduction in the amount offluid supplied through conduit I4 to circuit breaker I8 from reservoirI0; The cross sectional areas of conduit 58 and the portion 59 thereofas well as the cross sectional area of conduit Ill and the size ofspring II2 together with the location oi. bleed port H8 will be chosento cause piston I08 and valve I2 to assume the proper intermediateposition. It may be desirable further to delay the build-up of pressurewithin cylinder H0 and below piston I08 by the insertion in conduit Illof a relatively small reservoir such as that indicated by the numeralII8.

In order to cause the valve I2 to move from its partially opened orintermediate position to the bleed port H8 which is uncovered as soon asv the piston I" moves a short distance toward the valve closed position.The piston Hi8 moves to its uppermost position under the bias spring II2. fl'hus the device is quickly and automatically prepared for asucceeding cycle of operation.

It will be apparent to those skilled in the art that my invention is notlimited to the particular construction shown but that changes andmodiflcations may be made without departing trom the spirit and scope 01my invention and I intend in the appended claims to cover all suchchanges and modifications.

What I claim as new and desire to secure by Letters Patent. of theUnited States is:

1..A mechanism torcontrolling the flow of fluid from a source of fluidunder pressure to an'eleotric circuit breaker comprising a main valveoperative to opened, closed and intermediate positions, a rodoperatively connected to said main valve at one end and having aprojection at the other end, a cylinder through which said rod ismovable axially, a first piston secured to said rod and slidable in saidcylinder in response to fluid pressure from said source to move saidmain valve to its fully opened position, spring means for biasing saidfirst piston and main valve to the closed position, a second pistonwhich. is spring biased toward the projection on said rod and slidablymounted there'- on and disposed within said cylinder, a. partition insaid cylinder interposed between said pistons and dividing said cylinderinto two chambers, an opening in said partition through which said rodis slidable, and means including'ports on said rod for establishingcommunication between said chambers at a predetermined position of saidmain valve after the initiation of the opening movement thereof, wherebysaid main valve is moved to its intermediate position by pressure fluidacting on said second piston and by the action of the biasing springs.

2. A mechanism for controlling the flow oi? fluid from a source of fluidunder pressure to an electric circuit breaker comprising a main valvewhich is spring biased to closed position and operative to opened,closed and intermediate positions, a piston operatively connected tomain valve, a cylinder for said piston, a conduit interposed betweensaid source and said cylinder for supplying fluid to one side of saidpiston to cause said main valve to assume its fully opened position, asecond piston and cylinder associated with said first piston andoperative to move said main valve toward its closed. position. an auxiliary valve interposed between said source and said second cylinder andoperative at a predetermined time after initiation of the openingmovement of said main valve for supplying fluid under pressure to oneside of said second piston to cause said main valve to move to itsintermediate position, and an adjustable member disposed in the path offluid flowing through said auxiliary valve tor regulating the timerequired tor the main valve to move irom its fully opened position toits intermediate position.

3. A mechanism for controlling the flow o2 fluid from a source of fluidunder pressure to an electric circuit breaker, comprising a main valvewhich is spring biased to closed position and operative to opened,closed and intermediate positions, a piston operatively connected tosaid main valve, a cylinder for said piston, a conduit interposedbetween said source and said cylinder for supplying fluid to one side 01said piston to cause said main valve to assume its fully openedposition, an openin in said cylinder tor preventing the build-up ofpressure on the other side or said piston, a second piston and cylinderoperative to move said main valve toward its closed position. and anauxiliary valve interposed between said source and said second cylinderand operative at a predetermined time aiter initiation of the openingmovement of said main valve for supplying fluid under pressure to oneside of said second piston initially to provide a cushioned stop forsaid second piston and thereafter to cause said main valve to move toits intermediate position.

4. A mechanism for controlling the flow of fluid from a source of fluidunder pressure to an electric circuit breaker comprising a main valvewhich is spring biased to closed position and operative to opened,closed and intermediate positions, a rod operatively connected to saidmain valve at one end and having a projection at the other end, acylinder through which said rod is movable axially, a flrst pistonsecured to said rod and slidable in said cylinder in response to fluidpressure from said source to move said main valve to its fully openedposition, spring means for biasing said first piston and valve to theclosed position, a second piston which is spring biased toward theprojection on said rod and slidably mounted thereon and disposed withinsaid cylinder, a partition in said cylinder interposed between saidpistons and dividing said cylinder into two chambers, an

opening in said partition through which said rod. is slidable, and meansincluding ports on said rod for establishing communication between saidchambers after the initiation of the opening movement of said main valvefor tting fluid pressure to one side of said secondpiston to aid suchpiston and the biasing springs of both pistons in moving said rod andsaid :u; H. valve to the intermediate position.

5. A mechanism for controlling the flow o! fluid from a source of fluidunder pressure to an electric circuit breaker comprising a main valvewhich is operative to opened, closed and intermediate positions, a rodoperatively connected to said main valve at one end and having aprojection at the other end, a cylinder through which said rod ismovable axially, a first piston secured to said rod and slidable in saidcylinder in response to fluid pressure from said source to move saidmain valve to its fully opened position, a second piston of largerdiameter than said first piston and slidably mounted on said rod withinsaid cylinder, a partition in said cylinder interposed between saidpistons and dividing said cylinder into two chambers, an opening in saidpartition through which said rod is slidable, and means including portson said rod for establishing communication between said chambers afterthe initiation of the opening movement of said main valve whereby fluidpressure is admitted to one side of said second piston to 9 cause suchpiston to exert a force against said projection sufficient to move saidmain valve to the intermediate position.

6. A mechanism for controlling the flow of fluid from a source of fluidunder pressure to an electric circuit breaker comprising a main valvewhich is spring biased to closed position and operative to opened,closed, and intermediate positions, a piston operatively associated withsaid main valve, a cylinder for said piston, a first conduit interposedbetween said source and said cylinder for supplying fluid to one side ofsaid piston to cause said main valve to assume its fully openedposition, means including a second conduit of smaller cross-sectionalarea than said first conduit for supplying fluid to the other side ofsaid piston to cause said piston to move toward its intermediateposition at a predetermined time after said valve has occupied its fullyopened position, and a port in said cylinder for venting the fluid fromsaid second conduit to atmosphere upon being uncovered by said piston,said port being positioned to determine the intermediate position ofsaid piston and said main valve.

7. A mechanism for controlling the flow of fluid from a source of fluidunder pressure to an electric circuit breaker comprising a main valvewhich is spring biased to closed position and operative to opened,closed, and intermediate positions, a piston operatively associated withsaid main valve, a cylinder for said piston, a first conduit interposedbetween said source and said cylinder for supplying fluid to one side orsaid piston to cause said main valve to assume its fully openedposition, a second conduit for supplying fluid to the other side of saidpiston to cause said main valve to move toward its closed position, areservoir in said second conduit for delaying the build-up of fluidpressure on said other 40 .10 after said valve has moved to its openedposition, and a port in said cylinder for venting the fluid from saidsecond conduit to atmosphere, said port being positioned to determinethe intermediate position of said piston and said main valve.

8. A fluid-actuated operating mechanism comprising a cylinder, pistonmeans in said cylinder, biasing means normally restraining said pistonmeans in one position, means including valve means for supplying fluidpressure to one surface of said piston means to cause movement thereofto an operated position against the action of said biasing means, fluidpressure control means for admitting fluid pressure from said valvemeans to another surface of said piston means during movement of saidpistdn means toward its operated position, the build-up of pressure atsaid another surface being efiective together with said biasing means tomove said piston means toward its normal position, means for arrestingsaid last-mentioned movement of said piston means in an intermediateposition, said biasing means being efiective to return said piston meansto its normal position when the supply of fluid pressure to said pistonis cut off.

JULIUS W. TIMMERMAN, J R.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Germany Oct. 14, 1937

